Summary: Bought this bare-bone system to use as a media player for my parents. I put a core i7 with intel HD 4000 graphics which helps for high def video playing. Anything less I think will be a problem. It does not have any space for a custom video card so forget about that option!
Summary: Running i7 3770S, 16gb Ram, intel 240gb SSD. I have it running on a 1u rack shelf in a fairly confined 6u Gator case and getting very good temps (80-83C) while running prime95 burn-in test. Very happy with performance.
Summary: Perfect box, compact, sturdy, has 3 internal SATA ports (!) but only 1 2.5" can fit inside + mSATA drive. This box design is perfect - small form factor, almost silent, heavy, it feels like brick of steel.
Summary: pretty simple. add ram, cpu (no heatsink/fan, the case has one already) thermal pasted, and optional hard drive, and this thing's running away. using Debian 7 on it as a microserver. Works wonders headless!
Summary: I love this little PC! So fast and quiet. Yes, I can hear it running while mounted to the back of my monitor, but it doesn't bother me at all. I used an i3 processor and it really does perform flawlessly running Windows 7.
Summary: I purchased this to run as a router for my home network. I have a network larger than most folks, but I don't run a lot of features on my router. Sometimes I'll connect in remotely via VPN and I do run QoS, but that's about as taxing as I get with this.